Multiple chamber and bi-ventricular pacing is becoming a common therapeutic method for extending the life of patients with particular cardiac deficiencies. In order to achieve multiple chamber pacing, two or more leads are inserted into the same vein and guided through to the heart. Patients with implanted pacemakers may develop partial venous thrombosis as a result of leadwires residing in the veins. This occlusion can potentially interrupt the blood supply and become life-threatening. A promising solution to this problem are smaller leadwires, as they occlude less of the vein than larger diameter wires. BIOMEC's goal is to fabricate a micro stimulation leadwire, quantify its fatigue life relative to a reference coil, and statistically qualify its suitability for cardiac pacing. We will develop a new quad-polar pacing leadwire, which employs a construction that differs from conventional coaxial bipolar coiled wire leads. Our Four-Pole Micro-Stimulation Leadwire design is under 3 French (Fr) in diameter, occupying 90% less of the vein crossection than the 9 French coaxial bipolar leads in common use. We propose to fabricate samples and quantify the in-vitro fatigue characteristics of the MSL as the first step in demonstrating its effectiveness for three and four chamber stimulation of the heart. PROPOSED COMMERCIAL APPLICATIONS: The total arrhythmia management exceeded $4.5 billion last year. This market includes bradycardia implants, implantable cardioverter defibrillators (ICD), and external automated defibrillators. Specifically, in 1998 the forecast for bradycardial pacemaker implants exceeded 540,000 units worldwide, resulting in $2.6 billion in sale. The congestive heart failure market is expected to equal the bradycardia market annually. We expect that the benefit of smaller size and equivalent functionality will allow the MSL to be used in 10,000 procedures within the first year, or 2% of the total market. These sales will provide revenues greater than $22.5 million.